Dia - draw structured diagrams

Dia is a free application for drawing structured diagrams such as flow charts.

Dia is roughly inspired by Microsoft Visio, though more geared towards informal diagrams for casual use. It can be used to draw many different kinds of diagrams. It currently has special objects to help draw entity relationship diagrams, UML diagrams, flowcharts, network diagrams, and many other diagrams

The current version requires Windows 2000, XP or Vista (versions for Linux & Unix also available)